Margin 0 to 255 ? error

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trafficstars

LoRaWAN v1.0.2

14 The margin (Margin) is the demodulation signal-to-noise ratio in dB rounded to the nearest 15 integer value for the last successfully received DevStatusReq command. It is a signed 16 integer of 6 bits with a minimum value of -32 and a maximum value of 31.

line 1140 : LMIC.margin = m < 0 ? 0 : m > 254 ? 254 : m;

Isn't there a wrong value definition of the margin? I have some issue with my server not able to decode the received frame including device statut answer. The error is that margin can't be more than 31. I set an arbitrary value (12) for the margin and it worked. Did I miss something or does it need a correction?